Kitchen counterline apparatus



Oct. 29, 1963 F. D. LOW ETAL 3,103,754

KITCHEN COUNTERLINE APPARATUS Filed Aug. 29, 1960 2 Sheets-Sheet 1 INVENTOR. m g fl iz i BY a a1" an: er MA /W Hfiym United States Patent 3,168,754 KITCHEN COUNTERLENE APPARATUS Frank D. Low, La Grange Park, 111., and Walter L. Rancher, Gueendale. Wis, assignors to General Electric Company, a corporation of New York Filed Aug. 29, 19%, Ser. No. 52,380 Claims. (1. 241-36) The present invention relates to a kitchen counterline which includes the combination of a sink, dishwasher and food waste disposer and more particularly to automatic control circuitry for these devices.

The present invention is an improvement in a kitchen counterline of the type shown in US. Patent Number 2,813,534 which issued on November 19, 1957, to Frank D. Low. The counterline there shown, in which the effluent from the dishwasher discharges into the disposer chamber for passage therefrom to the plumbing drain, utilized control circuitry in which a pressure-sensitive flow switch allowed the food waste disposer motor to be started whenever an accumulation of waste in the disposer prevented free passage of dishwasher eihuent through the disposer to the drain. This automatic operation of the disposer caused the waste matter retained in the disposer to be comminuted and flushed out through the disposer drain, thus clearing the accumulation and permitting the dishwasher to operate in normal fashion. Although this mode of operation is mechanically and operationally sound, it was subject to a practical, or psychological, fault. When the flow of water from the dishwasher was backed up sufficiently to create the head of liquid necessary to actuate the water flow switch and start the disposer motor, the rotating disposer flywheel, by its pumping action within the disposer chamber, developed a low pressure area in the vicinity of the flow switch. This would give a false indication that the stoppage had been cleared, and the switch as a result would shut off after but a momentary operation. On shutting off of the motor, the low pressure area would dissipate itself and water pressure would again build up on the pressure sensitive flow switch to cause the motor to restart. Restarting the motor reactivates the flywheel which then produces the low pressure area a second time which in turn again causes the motor to shut off. This cycling would continue until finally the food waste was crushed sufficiently to drain. Such a cycling operation could be disturbing to the user. The present invention was designed to cure this operational fault.

It is therefore the principal object of the invention to provide in a combination as set out, a means for retaining the disposer motor operated once started by the pressure responsive water flow switch.

It is another object of the invention to provide a time delay device in a combination of the type described to maintain the disposer motor operated for a minimum amount of time to eliminate any waste blocking the disposer drain.

It is a feature of the invention to utilize a thermal delay device, a dashpot or other slow to react means to accomplish the aforementioned objects.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of the presently preferred embodiments thereof taken in conjunction with the accompanying drawings in which:

FIG. 1 is a front perspective view of a kitchen apparatus combination, including a sink, a food waste disposer and a dishwasher embodying the present invention;

FIG. 2 is an enlarged side sectional view of the food disposer of FIG. 1;

FIG. 3 is an alternative embodiment of the sectional view shown in FIG. 2;

ice

FIG. 4 is a diagrammatic illustration of a first embodiment of a circuit to operate said disposer;

FIG. 5 is a diagrammatic illustration of a second embodiment of a circuit to operate the disposer; and

FIG. 6 is a diagrammatic illustration of a third embodiment of a circuit to operate said disposer.

Referring to FIG. 1 of the drawings, the kitchen apparatus combination 10 there illustrated, and embodying the features of the present invention, is in the form of a kitchen counterline which includes a horizontally arranged counter top 11, supported by two adjacent cabinets 12 and 13 disposed therebelow, and terminating in an upstanding backsplash 14 arranged at the rear edge thereof. The left-hand section of the counter top 11 carries a sink depending therefrom into the left-hand cabinet 12; the bottom wall of the sink 115 carries a food waste disposer 16 depending therefrom and housed within the cabinet 12; and the cabinet 12 is provided with an open front that is normally closed by apair of front doors 17. The right-hand cabinet 13 houses a dishwasher schematically shown as 18, including an upstanding dishreceiving vat 19 provided with a front opening and a co operating door 20, also arranged in an aligned front opening provided in a front wall of the cabinet 13, the front door 21} being mounted adjacent the lower edge thereof for pivotal movement between a vertical closed position and a horizontal open position.

Accordingly, the dishwasher 18 is of the front-opening type and may be of the general construction and arrangement of that disclosed in US. Patent No. 2,657,695, granted on November 3, 1953, to Forrest A. Walker; whereby a sump is formed in the central portion of the bottom wall of the vat 19 in which an impeller 22 is arranged and rotated by a co-operating drive motor 23 carried by the bottom wall of the vat 19. An electric heating unit 24 is operatively associated with the impeller 22; and a drain conduit 25 communicates with the sump formed in the bottom wall of the vat 19. A spray device 26 is arranged in the upper portion of the vat 19 substantially centrally of the top wall thereof and carried thereby; which spray device 26 communicates with an inlet conduit 27 in which there is arranged an inlet valve 28 provided with an operating solenoid 28a. The inlet valve 28 is normally biased into its closed position and is operated into its open position upon energization of the solenoid 23a. Also, the dishwasher 13 comprises a drain pump 29 provided with an intake port communieating with the drain conduit 25 and a discharge port communicating with an upstanding discharge conduit 3%), the drain pump 29 being provided with an operating motor 31. Further, the dishwasher 18 comprises a program controller of any generally known type that is provided with a manually rotatable control dial 34 carried by the front wall adjacent to the upper left-hand corner of the cabinet 13. Further, door switches and other suitable controls may be employed in the generally known fashion.

The counter top 11 carries a faucet 42 disposed adjacent to the rear of the sink 15 and forwardly of the backsplash 14 and provided with a hot water valve 43 and a cold water valve 44, as well as a discharge spout 45 disposed over the sink 15. In thev kitchen, there is arranged a hot water supply pipe 46, a cold water supply pipe 47, and a drain pipe 48. The hot Water supply pipe 46 is connected both to the hot water valve 43 of the faucet 42 and to the inlet conduit 27 of the dishwasher 18; while the cold water supply pipe 47 is connected to the cold water valve 44 of the faucet 42.

A backsplash switch 52 is carried by the top of the backsplash 14 adjacent to the upper left-hand side thereof; and a flow control switch 54 is arranged in a side inlet provided in the disposer 16; which switches, and 54 are utilized for purposes more fully explained hereinafter.

The upstanding discharge pipe 36 extending from the discharge port of the drain pump 29 projects rearwardly and upwardly to a position behind the central portion of the backsplash 14, and the extreme outer end thereof is disposed above and in spaced relation to a co-operating funnel 55 within the backsplash 14 and arranged to receive flow from the pipe 30; whereby an air break is disposed between the end of the discharge pipe 30 and the funnel 55. In turn, the funnel 55 communicates with a conduit 56 that is connected to the side inlet of the disposer 16, as explained more fully hereinafter. It is obvious from the location of the disposer below the sink that the funnel inlet is substantially above the switch 54. As illustrated diagrammatically in FIGS. 4 and 6, the flow switch 54 comprises a bridging member 57, controlling an associated pair of contacts, as well as a resilient bellows 58 communicating with the conduit 56 and actuating the contact bridging member 57. In the arrangement, the bellows 53 normally biases the contact bridging member 57 into its open position; however, in

response to a backup of water in disposer 16 the bellows 58 is expanded, moving the contact bridging member 57 into its closed position.

Again referring to FIG. 1, the discharge outlet of the disposer 16 is connected by a substantially U-shaped trap 59 to the drain pipe 48 that extends exteriorly of the kitchen.

Referring now to FIG. 2, the disposer 16 essentially comprises an upstanding substantially tubular casing, including lower and upper sections 60 and 61. The casing sections and the method of securement of the disposer to the sink 15 may be as disclosed in Stoynich Patent 2,843,328 for Food Waste Disposer, patented July 15, 1958, and assigned to our present assignee. Briefly stated, for various methods of attachment of the disposer to the sink are in use in the art, and the specific attachment mechanism forms no part of the present invention, the section 61 terminates in an upstanding tubular throat 62 projecting into a drain opening 15a formed in the bottom wall of the sink 15 and carrying an outwardly directed annular flange 63 overhanging the adjacent marginal edge of the drain opening 15a. The disposer 16 is secured in place to the bottom wall of the sink 15 by an arrangement including an annular clamping ring 64 fixed to the lower portion of the tubular throat 62 and an intervening surrounding clamping collar 65 arranged above the clamping ring 66 and below the marginal edge of the drain opening 15a formed in the bottom wall of the sink 15. Section 61 is suspended from ring-64 by means of resilient material (not shown) secured within the clamping ring. More particularly three substantially equally angularly spacedapart set screws 66 are carried by the clamping ring 64 and projecting upwardly into engagement with the clamping collar 65 so as to urge the clamping collar 65 toward the annular flange 63 with the marginal edge of the sink 15 surrounding the drain opening 15a arranged therebetween, along with a suitable gasket 67 disposed between the upper surface of the clamping collar 65 and the lower marginal edge of the sink 15 surrounding the drain opening 15a. Accordingly, a food waste receiving chamber 68 is defined in the upper casing section 61 and communi cates through the tubular throat 62 with the interior of the sink 15; and removably arranged within the tubular throat 62 is a stopper-valve mechanism 69; whereby the interior of the chamber 68 is accessible through the tubular throat 62 from the sink 15 when the mechanism 69 occupies its removed position.

More particularly, the mechanism 69 comprises a substantially annular stopper or body portion 70 having a depending cylindrical sidewall 71. The sidewall has a number of spaced annular openings 72 which communicate with throat 62 when the mechanism 69 is raised to its drain position. At the upper end of the assembly 69, there is secured a handle 74 disposed in the tubular throat 62 and readily accesible from within the sink 15.

As is well known in the art, means (not shown) are provided to position the mechanism 69 within the throat 62 so that the openings 72 in the sidewall of the stopper permit water flow into the chamber 68 during operation of the disposer. Of course, it will be understood that it is necessary to remove the mechanism 69 completely from the tubular throat 62 in order to accommodate the deposit of waste food from the sink 15 through the tubular throat 62 into the chamber 68.

As more particularly illustrated in the Stoynich patent, in the lower portion of the upper casing section 61, that is, in the bottom of the chamber 68, there is disposed a shredding or comminuting ring 82 that co-operates with a number of hammers 83- carried by a flywheel 84 arranged in the bottom of the chamber 68; which flywheel 84 is carried by the operating shaft of an electric drive motor housed in the lower casing section 60 (the drive motor being indicated at SS in FIGS. 4-6). The extreme lower portion of the chamber 68 terminates in a discharge tube 86 (FIG. 1) and it is, in fact, this discharge tube 86 that is connected to the trap 5-9. A side inlet tube 87 is arranged in an opening provided in the upper casing section 61; and it is, in fact, the outer end of this inlet tube 87 that is connected to the conduit 56, as indicated in FIG. 1. In the arrangement, the inner end of the inlet tube 37 communicates withthe chamber 63 at a position well below the tubular throat 62 and well above the com-minuting ring 32. As is well known in the art,

the rapid rotation of flywheel 84 during disposer op-' eration creates a powerful centrifugal pumping action which may drive liquid outwardly through tube 87 and into its associated conduit 56. The Stoynich patent teaches the use of the baflle 90 upstream of the outlet port 89 of said tube, considered with reference to the direction of rotation of the flywheel and the liquid rotating therewith, to create a negative pressure in said tube 87 and conduit 56. In the circumstance of the presence of waste in the chamber 68 suflicient to restrict free drainage of liquid from the chamber, the infiowing dishwasher efliuent by operation of dishwasher pump 29 may accumulate within the chamber 68 until the inlet 89 is submerged, whereupon the hydrostatic head which builds up as the dishwasher continues to discharge its efliuent will cause the bellows 54 to operate its bridging contact to complete an energizing circuit for the disposer motor 85, as presently explained. It maintained for a sufficient interval, the operation of the disposer will clear the disposer of the waste and the accumulated liquid, and restore the normally easy drainage pattern from the disposer to the plumbing waste line, whereupon the eflluent discharging from the disposer would pass to the waste line without accumulation within the chamber 63. However, as taught in the Stoynich patent, the presence of the baffie 90 within the path of liquid flow in the chamber diverts centrifugally circulating water away from inlet port 89 and causes a low pressure promptly to develop in the area of the side inlet tube 87. Thus when pressure switch 54 has operated to start disposer motor rotating, flywheel 84 on rotation creates a low pressure region in tubes 87 and 88. Pressure switch 54 will then restore causing motor 85 and flywheel 84 to cease rotation. On cessation of rotation, the pressure acting on switch 54 would again rebuild it the Waste had not been fully comrninuted during this initial, brief, operation of the disposer and the switch would again operate to start the motor and flywheel. This stutter-like operation would continue until the waste in the disposer chamber 68 had been flushed down the drain.

In FIG. 3, there is shown an alternative location for a pump flow switch designated 54.1. The switch 54.1 includes a pressure sensitive diaphragm 58.1 forming a portion of the sidewall 61 of chamber 68. The diaphragm should preferably be installed in the area just above the shredding ring 82. This diaphragm on being constricted by pressure in the chamber actuates a bridging member 57.1 which in turn operates contacts similar to those de scribed for the prior embodiment. The functioning of pressure switch 54.1 is quite similar to that previously described for pressure or flow control switch 54. For this embodiment, when liquid begins to back up in chamber 68, diaphragm 58.1 is constricted by the pressure thus actuating bridging member 57.1 and its output contacts (not shown in FIG. 3). Motor 85 is thereby energized causing flywheel S3 to rotate. Rotation f the flywheel tends to displace the waste matter clogging the disposer drain holes and the liquid static level in the disposer chamber drops causing a low pressure region adjacent diaphragm 53.1. This low pressure distends diaphragm 53.1 which causes bridging member 57.1 to restore its closed contacts and open the circuit to the disposer motor.

The present invention provides time delaying means actuated concurrently with the disposer motor on a buildup of efiluent in the disposer and once actuated maintains the motor operated for a period suflicient to comminute the blocking waste matter for subsequent flushing of the efiiuent down the drain.

It should be noted in analyzing the circuitry of the invention that the circuits of FIGS. 4-6 are explained as applied only to switch 54 and its operation but it can readily be seen that the forthcoming circuit explanation is equally applicable to switch 54.1 as disclosed in FIG. 3. Each of these switches, 54 and 54.1, is the functioning equivalent of the other and either could be used in the circuits to be explained with no other change in the circuit. Hence, it would serve no worthwhile purpose to explain each circuit embodiment with respect to both pressure sensing switches and no attempt has been made to do this. 1

Referring now to the circuits shown in FIGS. 4-6 there is shown a pair of power leads 91 and 92 which may be connected to a conventional 118 volt alternating current source (not shown). Connected to power lead 92 is a first circuit including disposer motor 85. 'From the disposer motor a lead 93 is connected to one contact of backsplasher switch 52 (shown in its open condition). The other contact of switch 52 is connected by lead 94 to the other side of the line at lead 91. Intermediate lead 93 also is connected to contact 95 of the normally open pump iiow switch 54. In each embodiment, contact 95 of the pump flow switch is also arranged to be connected to a delay circuit shown as 100 in FIG. 4,1111 in FIG. 5 and 192 in FIG. 6. Delay circuits 100 and 162 each include a parallel circuit path to lead 1% which is connected to the dishwasher 18 shown diagrammatically as a box. The dishwasher 18 is shown connected to the power leads including a first circuit to lead 92, and a second circuit through switch contacts 18.1 to power lead 91. The dishwasher, of course, has all the components and controls previously described and generally known, including contacts 18.1 which are closed at least during the drain cycle of the dishwasher and may physically take any generally known form such as timer cam actuated spring contacts.

By the circuitry of FIGS. 46, two alternate paths for the energization of disposer motor are possible. The

first of these may be traced from power lead 91, through backsplasher switch 52, disposer motor 85 to the other power lead 92. This energization path is the one used when the disposer is to be operated directly without reference to the dishwasher. The second energization path (shown in one embodiment in FIG. 4) may be traced from power lead 92, through the disposer motor 35, lead Q3 contacts 95, 5'7 and 96 of switch 54, delay circuit 100, swi-tch18.1 of dishwasher 18 and power lead 91. This second path is the one utilized when drainage from the operating dishwasher causes the pump cfiow switch 54 to close. A slightly different second energization path is used for FIGS. 5 and 6 as will be described more fully later in this specification.

The delay circuit 100 of FIG. 4 may be seen to comprise a thermally operated switch having its heater 105 in series with the motor. Bimetal actuated switch 106 parallels the series circuit formed by the pressure switch contacts 95 and 96 and heater 105. This bimetal switch is physically located proximately to the heater 105 to respond to the elevated temperatures generated by the heater. Optionally a shunt resistor 16'? may be connected across the heater 1115 as shown in FIG. 4 to reduce the amount of current flow through the heater 1115. In this embodiment, contacts 156 are normally open. pressure switch 54 actuates contact bar 57 and closes the circuit to the disposer motor and heater 105 in series, the heater tends to heat rapidly to a sufiicient degree to thermally actuate and close switch 1116 which when closed shunts out the pressure switch contacts and heater 165. Once closed, contacts of switch 106 remain closed for a timed period after the release of the pressure switch contacts. This contact closure maintains motor energized while shunting out heater 105-. Bimetal actuated switch 1% proceeds to cool down and on expiration of a predetermined timed period switch 106 restores. Restoration of switch 106 releases the shunt path to heater 1135 and motor 85. Except in situations of unusual or tenacious waste accumulations, the time during which switch 196 maintains operation of the disposer motor 85 is sufiicient to clear the stoppage, whereupon there will be no reaccumulation of liquid within the chamber 68, and the motor 85 will remain oil for the remainder of the dishwasher discharge operation. On the other hand, if the stoppage persists, the dishwasher eflluent will again rise to cause switch 54- to restore motor operation, and operation of the time-delay switch 106, for a renewed operation of the motor 85.

The circuit 1111 of FIG. 5 includes a minor change in the structure of the bridging element 57 as used in FIGS. 4 and 6. In the embodiment of FIG. 5, the bridging element is replaced by a striker arm 111 acting against armature cont-actor 112-. Armature contactor 112, for maxi mum effectiveness would be of bi-metal construction and would be constructed into its contact assembly in a snap action over-center method wellaknown in relay and bimetal relay art. A heater element 113 is placed physically close to bi-metal contactor 112 and electrically is connected in parallel with disposer motor. In this embodiment, contactor 112 is in a normally open circuit relationship with stationary contact 95. The operation of this circuit embodiment is as follows: When the water pressure in inlet duct '87 causes pressure switch 54 to actuate its bellows 58', striker arm 111 is deflected and strikes armature contactor 112 causing contactor 112 to close its circuit to stationary contact 95. This closed circuit causes disposer motor '85 and heater 113 to be energized through closed dishwasher contacts 18.1. By virtue of its over-center characteristics, armature 112 will remain closed to contact even when striker arm 111 releases its pressure on the armature due to a decrease in duct pressure. Motor 85 will continue to be energized through armature 112 and 95 as will be heater 113. The heater will then heat raising the temperature of the bi-metal armature. When the heater has [heated to a sufiiciently high temperature, bi-rnetal armature 112 will flex and snap-actingly restore thus opening the circuit to the heater and motor. If by the conclusion of this timed heating period, the striker arm has not released its pressure on armature 112, the bi-metal armature will continue to keep the circuit to disposer motor 85 and heater 113 closed under the control of the pressure switch 54. When in this situation, the pressure switch restores, armature 112 having been continuously heated will also remain in its restored state. As the armature cools after restoration of the pressure switch, it will remain in its open condition, as mentioned, due to its over-center snap action. Recapitulating, the thermal relay of FIG. 5 is a bi-stable normally open relay which requires physical pressure to close. Once closed, the relay will remain in that con- When the dition until released both by thermal action on its bimetal elements and by release of the physical pressure.

The circuit of PEG. 6 utilizes a delay circuit 1% including an electromagnetic relay 121 having magnetically operated normally open contacts 122. Contacts 12?. parallel the pressure switch contacts electrically speaking. Relay 121 is connected electrically in series with thermally actuated bimetal switch 123 which is normally biased to closed position. A heater 124 for switch 123 is connected in parallel with the previously mentioned series circuit and physically proximate to said switch 123.

The operation of the circuit or FIG. 6 is as follows: When the pressure switch 54 is actuated and the contacts 95% have closed, a circuit is completed to the disposer motor 85 through dishwasher contacts 18.1. Parallel circuits are also closed to heater 124- and the relay operas ing circuit. Within the relay circuit, relay 121 operates through'the normally closed bi-metal contacts and loclrs up its own contacts 122. Contacts 122 shunt out the pressure switch contacts which may and usually do re lease sporadically. Relay 121 is maintained energized through closed contacts 122 and 123 until heater 12 i heats switch 123 sutliciently to open the contacts thereof. The relay operating path is thus opened, after which the relay will restore. Restoration of the relay opens contacts 122 and the shunt path across pressure switch contacts 9596. Thus in this embodiment there are two consequent timed periods during which the disposer is held operated. These periods, the bi-metal relay release period and the consequent electromagnetic relay release period, may be set by varying the circuit parameters to vary the motor hold time.

Considering now the normal operation of the disposer 16, when the housewife has food waste that is to be disposed, she removes the stopper-valve mechanism 69, and then deposits the food waste through the tubular throat 62 into the chamber 63, and then returns the stoppervalve mechanism 69 into the tubular throat 62 in the FIG. 2 position, in which the openings '72 accommodate water flow from the sink into the chamber 6?. Next, the housewife opens the cold water valve 44 of the faucet 42; whereby the cold water from the cold water supply pipe 47 passes through the spout 4 5 of the faucet 42 into the sink 15 and runs through the stopper-valve mechanism 69 and into the chamber 63. Then the housewife opcrates the backspl-ash switch 52 into its closed position; whereby an obvious circuit is completed for operating the disposer motor 85 so that the disposer 16 is operated to bring about shredding or comminuting oi the food waste and the consequent flushing of the resulting material therefrom and through the drain pipe 4% to the exterior. In order to arrest operation of the disposer motor 35, the backsplash switch 52 may be manually operated into its open position.

The second mode of operation of the disposer may be, as previously mentioned, through the agency of the dishwasher and the dishwasher drain system. It is assume for the foregoing description that the necessary dishwasher controls are all in their closed position and that contacts 18.1 are also closed. Contacts 18.1 serve to illustrate suitable timer actuated cairn contacts within the dishwasher which are closed when the dishwasher draining operation is in process. Waste liquid will then flow through drain conduit 25, drain pump 29, discharge conduit 3% funnel 55 and conduit 56 to the alternate disposer inlet tube 87. it while the waste from the dishwasher flows into the disposer, there has accumulated unshredded waste matter in the disposer chamber, water will back up in tube 87. Backup of water in the tube will cause motor 85 to acrtuate over the previously described circuit. In the FIG. 2 embodiment, as the disposer flywheel drives the contents of the chamber against the wall of the chamber, the flywheel pumps the contents against batlle 9% to perform what has been termed an anti-pumping action. his action almost immediately causes a low pressure region at the chamber opening 87. This pressure reduction in the area of pressure switch 54 causes the pressure switch to release soon after the actuation of the motor. It is at this stage that the previously described function of the time delay device comes into play. The time delay device whether it be 1G0, 161 or 102 maintains the disposer motor operative for the delay period which may be preset to be sufiicient to normally shred and flush out accumulated waste. When the accumulated waste is cleaned out, the disposer may drain the liquid from the dishwasher readily.

In the embodiment of FIG. =3, the low pressure at diaphragm 58.1 is generated (as mentioned) by the rotation of flywheel which displaces the matter blocking the normal drainage and causing a dissipation of the static water head at the level of switch 54.1. This low pressure will cause switch 54.1 to release while the delay circuit operates.

While there has been described what is presently considered to be the preferred embodiments of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. In a kitchen appliance comprising a food waste disposer having a waste-receiving chamber, comminuting means at the base of said chamber, an electric motor for operating said comminuting mean to discharge comminuted waste to a plumbing drain, and a liquid conduit system including said chamber and piping entering said chamber to discharge liquid thereinto: the improvement comprising pressure sensitive means openly communicating with said liquid conduit system and responsive to the hydrostatic pressure therein; an electric circuit including normally open switch means efiective when closed to energize said disposer motor; means actuated by said pressure sensitive means in response to a predetermined increase in hydrostatic pressure to close said switch means; an electric circuit in parallel with said motor energizing circuit; and means actuated to energize said second named electric circuit to maintain said energized motor circuit for a substantial interval following a reduction in hydrostatic pressure below the level sutlicient to maintain said switch means in closed circuit condition.

2. In a kitchen applicance comprising a food waste disposer having waste comminution means and an elec rtric motor for actuating said means to discharge comminuted waste to a plumbing line, an electric circuit for energizing said motor, normally open switch means in said circuit, a conduit for bringing liquid into said disposer above the comminution means thereof, and means responsive to a predetermined increase in hydrostatic pressure within said conduit to operate said switch to closed circuit condition: the improvement comprising a shunting circuit for energizing said disposer motor in parallel with said first circuit, a normally open switch in said shunting circuit, means responsive to the closure of said first-named switch to operate said shunting circuit v switch to closed circuit condition, and means for maintaining said shunting circuit switch closed for a substantial interval following the opening of said first-named switch.

3. The improvement according to claim 2, in which said shunting circuit switch is thermally operable to closed circuit condition, and said first named energizing circuit includes a resistance heating element in heat transfer relation to said shunting circuit switch.

4. In a kitchen appliance comprising a food waste disposer having a waste-receiving chamber, comminuting means at the base of said chamber, an electric motor for operating said comminuting means to discharge comminuted waste to a plumbing drain, a circuit for energizing said motor, and a liquid conduit system including said chamber and piping entering said chamber to discharge liquid thcreinto: the improvement comprising pressure sensitive means openly communicating with said liquid conduit system and responsive to the hydrostatic pressure therein, electrical relay means including a first normally open switch means in an energizing circuit for said disposer motor, a second normally open switch means in a parallel motor energizing circuit, said second switch means being arranged to be actuated to closed circuit condition by said pressure sensitive means in response to a predetermined increase in hydrostatic pressure; a circuit for energizing said relay to close said first named motor energizing circuit, said last named circuit including said second-named switch and a normally closed thermally actuatable switch; and a resistance heating element in circuit with said first and said second-named switch to provide heat energy for opening said thermally actuatable switch upon closure of either of said switches.

5. In a kitchen appliance comprising a food waste disposer having a waste-receiving chamber, comminuting means therein, an electric motor for operating said comminuting means to discharge comminuted waste to a plumbing drain, and a liquid conduit system including said chamber and piping communicating therewith: the improvement comprising pressure-sensitive means communicating with said liquid conduit system for response to the hydrostatic pressure therein, an electric energy circuit for said motor, a normally open switch of the bistable thermostatic type in said circuit, means comprising a plunger actuated by said pressure-sensitive means in response to a predetermined hydrostatic pressure to operate said switch to complete said motor energizing circuit, and electric circuit means in parallel with said motor and arranged to be energized therewith upon closure of said switch, said last-named circuit including a resistance heating element in heat transfer relation with said switch to restore said switch to open circuit condition.

References Cited in the file of this patent UNITED STATES PATENTS 2,244,402 Powers June 3, 1941 2,615,636 Powers Oct. 28, 1952 2,664,247 Jordan Dec. 29, 1953 2,678,775 Simmons May 18, 1954 2,699,294 Johnson Ian. 11, 1955 2,750,121 Schimidt June 12, 1956 2,813,534 Low Nov. 19, 1957 FOREIGN PATENTS 1,124,599 France July 2, 1956 

1. IN A KITCHEN APPLIANCE COMPRISING A FOOD WASTE DISPOSER HAVING A WASTE-RECEIVING CHAMBER, COMMINUTING MEANS AT THE BASE OF SAID CHAMBER, AN ELECTRIC MOTOR FOR OPERATING SAID COMMINUTING MEANS TO DISCHARGE COMMINUTED WASTE TO A PLUMBING DRAIN, AND A LIQUID CONDUIT SYSTEM INCLUDING SAID CHAMBER AND PIPING ENTERING SAID CHAMBER TO DISCHARGE LIQUID THEREINTO: THE IMPROVEMENT COMPRISING PRESSURE SENSITIVE MEANS OPENLY COMMUNICATING WITH SAID LIQUID CONDUIT SYSTEM AND RESPONSIVE TO THE HYDROSTATIC PRESSURE THEREIN; AN ELECTRIC CIRCUIT INCLUDING NORMALLY OPEN SWITCH MEANS EFFECTIVE WHEN CLOSED TO ENERGIZE SAID DISPOSER MOTOR; MEANS ACTUATED BY SAID PRESSURE SENSITIVE MEANS IN RESPONSE TO A PREDETERMINED INCREASE IN HYDROSTATIC PRESSURE TO CLOSE SAID SWITCH MEANS; AN ELECTRIC CIRCUIT IN PARALLEL WITH SAID MOTOR ENERGIZING CIRCUIT; AND MEANS ACTUATED TO ENERGIZE SAID SECOND NAMED ELECTRIC CIRCUIT TO MAINTAIN SAID ENERGIZING MOTOR CIRCUIT FOR A SUBSTANTIAL INTERVAL FOLLOWING A REDUCTION IN HYDROSTATIC PRESSURE BELOW THE LEVEL SUFFICIENT TO MAINTAIN SAID SWITCH MEANS IN CLOSED CIRCUIT CONDITION. 